Solar Warranties Explained: Product, Performance, Inverter & Workmanship

The product warranty covers the panel itself failing from a defect in materials or workmanship — a bad cell, junction box, frame or glass. It is honored by the panel maker, and terms now vary widely: 12 years on some lines, 25 on others, 40 on one. The longer terms often depend on who installs and registers the panels, so ask which term applies to your install, in writing. What you receive on a valid claim — repair, replacement (sometimes with a refurbished unit) or a refund — is set by each warranty document.

The performance warranty guarantees a minimum power output as the panel ages. Current ones are linear: a floor for year 1, then a fixed maximum loss each year — Maxeon 98% in year 1 and then 0.25% a year, Silfab 98% and then no more than 0.30% a year to year 30, REC 0.25% a year to at least 92% in year 25. The test is the panel’s own power under standard test conditions, so dirt, shade and heat on your roof don’t count against it; solar panel degradation shows how real systems compare with these floors.

Not the same as a production guarantee. A performance warranty covers one panel’s rated power. A minimum-energy (production) guarantee covers the kilowatt-hours the whole system makes; the CPUC’s consumer guide notes it is common with leases and power purchase agreements and suggests asking how you would be compensated if the system underproduces (CPUC).

The inverter maker covers the electronics that turn panel power into household power. Enphase covers its IQ7, IQ8 and IQ9 microinverters for 25 years from activation, but the monitoring and control parts around them for less: 5 years on the IQ Gateway and IQ Combiner, 10 on the IQ System Controller (Enphase). SolarEdge covers its power optimizers for 25 years and its inverters for 12 — 10 for the new Nexis — with communication devices at 5 (SolarEdge); Home Hub and Home Wave inverters can be extended to 20 or 25 years within a set window after shipment, $170–$225 to take a Home Hub to 25 years on its early-2026 price list. The CPUC’s guide singles out the inverter as the part that may need replacing sooner than the rest, so keep that warranty where you can find it. How the two systems compare is in Enphase vs SolarEdge.

The workmanship warranty covers the installation itself — mounting, flashing and sealing of roof penetrations, wiring — and it is the only one backed by your installer rather than a manufacturer. Its term is whatever your contract says, so get it in writing: the Contractors State License Board tells consumers to get any labor and material warranty in writing (CSLB), and the CPUC’s guide lists “Are there warranties for labor/construction?” among the questions to ask. Two roof questions from the same guide belong in that conversation: what steps the installer will take to make sure the roof won’t leak, and roughly what it would cost to remove and reinstall the panels if the roof needs replacing later (see removing and reinstalling panels for a new roof).

For a public benchmark, California’s Self-Generation Incentive Program sets minimums for solar in the projects it funds: a 10-year workmanship warranty for no-cost repair and replacement of anything the manufacturer doesn’t cover, a 20-year installer warranty against more than a 10% output loss caused by faulty installation, and 20-year performance warranties on panels and inverters against more than a 15% loss (SGIP Handbook 2026, §8.1). Those rules bind only SGIP-funded projects, but they show what a complete package covers.

A battery wears with use, so its warranty has three limits — years, a cycle or throughput cap, and a minimum retained capacity — and coverage ends at whichever comes first. Tesla covers Powerwall 3 for 10 years and guarantees 70% of its 13.5 kWh at year 10, with unlimited cycles for solar self-consumption, time-based control and backup, and a 37.8 MWh throughput cap for other uses (Tesla). Enphase covers the IQ Battery 5P for 15 years or 6,000 discharged cycles, guaranteeing 70% at year 10 and 60% at the end (Enphase). FranklinWH covers the aPower 2 for 15 years or 60 MWh, with 70% at the end (FranklinWH). For batteries it funds, SGIP requires at least a 10-year performance warranty guaranteeing 60% of the starting capacity at year 10. The three side by side: Powerwall vs Enphase vs FranklinWH.

A clear proposal names, for each layer, the term and who honors it: panel product years, the performance floor, inverter years (and whether an extension is included), workmanship years, and a battery’s three limits. Then ask the questions from the CPUC’s consumer guide: whom you contact to replace a failed part, what an inverter costs to replace after its warranty, whether labor and construction are warranted, and whether repairs and maintenance are included (CPUC). A vague “25-year warranty” is a reason to ask for the itemized version before you sign, not proof of anything by itself.

Figures on this page come from the primary sources below and, where noted, from Cali Energy calculations using the stated assumptions. Rates, incentives, and program terms change; each was verified September 29, 2026.

1. REC — Alpha Pure-RX series (20-year product warranty, 25 with ProTrust; at least 92% at year 25)
2. REC — ProTrust warranty (25 years product, performance and labor up to 25 kW; 10-year labor for 25–500 kW)
3. Qcells — Q.TRON BLK M-G2+ (25-year product warranty, at least 90.58% at year 25)
4. Maxeon — Limited Warranty for PV Modules (document 545700, Rev G, effective May 1, 2026)
5. Silfab Solar — Limited Product and Linear Performance Warranty (SIL-CS-WRTY-010, Rev Q)
6. Canadian Solar — TOPHiKu6 datasheet and warranty terms
7. Enphase — US Limited Warranty, IQ Microinverters and balance of system (effective May 2, 2026)
8. Enphase — Labor reimbursement for warranty service, North America (effective February 1, 2026)
9. Enphase — US Limited Warranty, IQ Battery 5P (effective May 2, 2026)
10. SolarEdge — Limited Product Warranty (effective January 1, 2026)
11. SolarEdge — North America warranty extension price list
12. Tesla — Powerwall Limited Warranty (USA), Rev. 2.6
13. FranklinWH — system limited warranty for end users
14. SGIP — 2026 Handbook (V3), §8.1 warranty requirements (resources page)
15. CPUC — California Solar Consumer Protection Guide
16. CSLB — Home improvement contracts (get labor and material warranties in writing)